In particular the invention relates to a concealed hinge for a turn-tilt window that can turn open around a vertical axis, and can tilt open around a horizontal axis, depending on the position of the operating handle of the window.
Such concealed hinges are mounted in a concealed way between the fixed frame and the leaf or are intended for this purpose, so that they are not visible when the window is closed.
As is known, the leaf is provided along its periphery with a sidelong leaf lip protruding outwards, whereby in the closed position of the window the leaf rests against the front of the fixed frame through the intervention of a seal, whereby the leaf lip partially overlaps the frame in the front view.
This leaf lip also covers the space between the leaf and the fixed frame in which the concealed hinges are mounted, so that they are concealed from view when the window is closed.
The leaf is turnably suspended in the frame by means of two hinges, respectively a bottom hinge and a top hinge that are mounted respectively on the bottom and top of the leaf.
The top hinge is constructed in a known way with a scissor mechanism that can be blocked with respect to the leaf to enable a turn of the leaf around a vertical axis or can be unblocked to enable the tilting of the leaf around a horizontal axis.
The bottom hinge enables both a turning movement and a tilting movement.
Conventionally a turn-tilt window is provided with fittings with fitting slats that are shiftably affixed in a fitting groove along the outer periphery of the leaf, whereby the fitting slats are shifted in the one or the other direction in the fitting groove by means of an operating handle that can be turned from the closed position to a turn or tilt position depending on whether the person wants to turn open or tilt open the window.
In the turn position of the operating handle the aforementioned scissor mechanism is blocked by the movement of the fitting slats, such that the leaf can turn open.
In the tilt position the scissor mechanism of the top hinge is unblocked such that a tilting movement of the leaf is possible. This is often realised around an axis in the section of the bottom hinge that is fastened to the leaf or by deformation of the hinge.
A disadvantage of known concealed hinges is that the horizontal axis around which the leaf can tilt is relatively far above the bottom profile of the frame of the window, which can be detrimental for low windows, for example for windows with a height that is less than 50 cm, which due to their low height only enable a limited tilting movement with a limited opening angle, because otherwise the bottom leaf lip would touch the front of the frame with its seal, such that the seal could be crushed or the leaf lip damaged.
With known concealed hinges the mounting of the leaf in the frame is relatively complicated, as in certain steps of the assembly the installer cannot see the hinges and thus has to rely on touch. This requires sufficient knowledge and skill on the part of the installer.